112 THE EEJuATIONS OF MAN 



fixed to the long flexor tendons — or by a multiplication of 

 the slips. — Again, the Gorilla differs slightly from Man in 

 the mode of interlacing of the long flexor tendons : and the 

 lower apes differ from the Gorilla in exhibiting yet other, 

 sometimes very complex, arrangements of the same parts, 

 and occasionally in the absence of the accessory fleshy 



bundle. 



Throughout all these modifications it must be recol- 

 lected that the foot loses no one of its essential characters. 

 Every Monkey and Lemur exhibits the characteristic ar- 

 rangement of tarsal bones, possesses a short flexor and 

 short extensor muscle, and ^peronoeus longus. Varied as 

 the proportions and appearance of the organ may be, the 

 terminal division of the hind limb remains, in plan and 

 principle of construction, a foot, and never, in those re- 

 spects, can be confounded with a hand. 



Hardly any part of the bodily frame, then, could be 

 found better calculated to illustrate the truth that the 

 structural differences between Man and the highest Ape 

 are of less value than those between the highest and the 

 lower Apes, than the hand or the foot, and yet, perhaps, 

 there is one organ the study of which enforces the same 

 conclusion in a still more striking manner — and that is 

 the Brain. 



But before entering upon the precise question of the 

 amount of difference between the Ape's brain and that of 

 Man, it is necessary that we should clearly understand 

 what constitutes a great, and what a small difference in 

 cerebral structure ; and we shall be best enabled to do 

 this by a brief study of the chief modifications which the 

 brain exhibits in the series of vertebrate animals. 



The brain of a fish is very small, compared with the 

 spinal cord into which it is continued, and with the nerves 

 which come off from it : of the segments of which it is 



